Accurate analysis of nucleic acids having a limited mass is required for many applications. When nucleic acids have an insufficient mass to be sequenced directly, a process of amplification is required. High fidelity amplification is essential so as to ensure an accurate representation of the template, which, in turn, can affect the accuracy of any downstream measurement. This process is required for applications where there are only small numbers of cells (including only one cell) available for analysis.
For example, preimplantation genetic diagnosis (PGD) can be used to determine whether a specific embryo has a genetic abnormality or known aberration that could lead to either failed implantation, subsequent miscarriage or the birth of a child with physical and/or developmental disability. The diagnosis can be used to make decisions on which embryo(s) should be transferred to the uterus for implantation and will with high likelihood result in a normal pregnancy.
PGD can be performed on genomic DNA from cells that are biopsied from embryos. Because the quantity of genomic DNA extracted from this biopsy can be insufficient for current genomic analysis techniques, including DNA sequencing, the DNA is typically amplified. In performing this amplification, a requirement is to accurately represent the state of the embryonic genome in the amplified product. However, amplification methods can result in an over-representation of certain regions of the genome and an under-representation of others, a phenomenon known as “amplification bias”. This bias can render the amplification products a distorted version of the original genomic DNA and thus limit the accuracy of PGD.
The present invention addresses this and other needs by providing methods, devices and systems to perform high fidelity amplification of nucleic acids with the goal of accurately analyzing nucleic acids from samples with limited template mass. These methods and devices can be used for numerous applications, including but not limited to PGD.